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In the recent InDesign versions, the Justification alternates feature is completely failing in OpenType fonts

Forum|Forum|20 days ago
June 13, 2026
4 replies
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In the recent InDesign versions Adobe has introduced HarfBuzz as the default text shaping engine but the Justification alternates feature is now not working in OpenType fonts at all, we have confirmed it by testing Arabic fonts. For Adobe text rendering engine this feature still works seamlessly but for Harfbuzz this fails silently. Is there some compatibility issue of Harfbuzz with Adobe paragraph model or we are missing something as we have tested several fonts with same result?

It has disturbed all our past documents as the users use this feature in the whole documents to beautifully justify the paragraphs using justification alternates.

Correct answer Eugene Tyson

You aren’t missing a font setting here you've actually run into a genuine integration bug.

To break down what's happening under the hood. HarfBuzz is fully capable of processing the OpenType jalt (Justification Alternates) feature, but HarfBuzz itself doesn’t handle paragraph justification. Its only job is to shape the text runs it's given. It’s up to InDesign’s paragraph composer to figure out where those justification alternates are needed, and then explicitly pass those specific character ranges over to HarfBuzz.

In fact, the OpenType spec explicitly puts this responsibility on the host application. The jalt feature is supposed to be triggered by the justification algorithm, which then calculates the new line lengths during composition.

Because this works perfectly fine with Adobe’s legacy shaping engine but gets completely ignored by HarfBuzz, it strongly points to a regression in how InDesign integrates with HarfBuzz, rather than an issue with the OpenType fonts themselves. Adobe’s documentation still lists Justification Alternates as a supported World-Ready feature (specifically naming fonts like Adobe Arabic, Myriad Arabic, and Adobe Naskh) with no mention of an exception for HarfBuzz that I can find.

The Temporary Workaround
For now, your best bet is to revert to the old behaviour:

Go to Preferences > Advanced Type and check Enable Legacy Text Shaping for Adobe World-Ready Composer.

This is Adobe’s official fallback for rendering issues, but keep in mind that switching shaping engines can cause text to reflow. Definitely double-check your documents for altered line endings, overset text, or pagination shifts before sending anything to print or export.

Filing the Bug Report
This is absolutely worth reporting as a reproducible InDesign bug. To give it the best chance of getting fixed, I'd recommend creating a minimal test document using a standard font like Adobe Naskh and listing these steps:

Apply the World-Ready Paragraph Composer.

Fully justify the Arabic paragraph.

Enable Justification Alternates.

Compare the broken result under HarfBuzz with the correct result under Legacy Text Shaping.

Report here

https://indesign.uservoice.com/forums/601180-adobe-indesign-bugs

I’d frame it as “Justification Alternates (jalt) ignored by the HarfBuzz World-Ready shaping workflow” rather than saying the feature fails for all OpenType fonts. Since only specific fonts actually include the jalt feature, narrowing it down to the HarfBuzz integration will help the engineering team pinpoint the issue much faster.

D

Dirk Becker

Legend

When you select all text and look at the language, what do you see there? For me it’s English: UK, and switching to Arabic causes some shuffle.

zuhair777Author

Inspiring

Yes, it is English (UK), and switching to Arabic clearly causes some shuffling.

D

Dirk Becker

Legend

Document history says you used version 19.0 to create that document, is that for any specific reason? I think that was a very early Harfbuzz composer flavour, and a recompose in a more recent version should cause more changes. If I force recompose in my 19.4 I already get several changes.

Abhishek Rao

Community Manager

Hi @zuhair777,

Thank you for reporting this and for taking the time to file a bug report. Could you please share the UserVoice link you created so I can take a look at it as well?

Also, if possible, could you share a short screen recording demonstrating the issue in action? It would be very helpful to see the same text and font with Justification Alternates enabled under both the HarfBuzz shaping engine and Adobe Legacy Text Shaping for comparison.

I tried reproducing the behavior on my end and was able to see Justification Alternates being applied with HarfBuzz, so I'd like to compare your workflow against my test setup to understand whether I'm missing a specific condition, font behavior, or document setting that triggers the issue.

Looking forward to your update.

Abhishek

zuhair777Author

Inspiring

Hi @Abhishek Rao

Thank you for looking into this issue.

I have tried to demonstrate the issue with a video and 4 images, the document is also attached. I have already tested it with this document, so I applied red color to some words that change when the feature is applied. Adobe Naskh font is used. I used a script to toggle between the text engines.

First, I tried with HarfBuzz. Adobe World-Ready Paragraph was applied, Kashida was set to None in the menu bar (in this Arabic-enabled English InDesign), and then justification alternates were applied. HarfBuzz is not showing any justification alternate.

Then, I changed the text engine to Adobe Legacy Engine and applied the same steps. You can observe that longer swashes appeared at random places in the text (already marked in red).

I have not created any UserVoice link, it may have been created by mistake.

short video indesign document

image 1 image 2 image 3 image 4

Thanks,

Abhishek Rao

Community Manager

Hi @zuhair777,

Thank you for sharing the detailed information, screenshots, video, and sample document.

Let me take some time to test this further on my end and review the behavior more closely. I'll also discuss the findings with the product team to understand whether this is a known issue related to the HarfBuzz text shaping engine.

I'll update this thread once I have more information.

Thanks again for your help and for providing the repro materials.

Abhishek

zuhair777Author

Inspiring

Thank you @Eugene Tyson for your help. I have reported the bug.

E

Eugene Tyson

Correct answer

Community Expert